Flaw detector mechanism



Jan. 18, 1938. H. c. DRAKE 2,106,050

FLAW DETECTOR MECHANI SM Filed Oct. 28, 1933 40 INVEN TOR Patented Jan. 18, 1938 FLAW DETECTOR MECHANISM Harcourt C. Drake, Hempstead, N. Y., assignor to Sperry Products, Inc., Brooklyn, N. Y., a corporation of New York Application October 28, 1933, Serial No. 695,611

1 Claim.

This invention relates to rail fissure detector mechanisms of the type employed in the Sperry rail fissure detector car. As is now well known, said cars travel over the rails and when a flaw is detected a paint gun is operated to discharge paint upon the rails in order to mark the position of the flaw.

It is the principal object of this invention to provide an improvement in the Sperry rail fissure detector car which will insure operation of the paint gun regardless of the shortness of the duration of energization due to the small size of the flaw and the speed of travel of the car over the rails.

Other objects and advantages of this invention will become apparent in the following detailed description thereof.

In the accompanying drawing,

Fig. 1 is a-side elevation of a portion of a Sperry rail fissure detector car.

Fig. 2 is a wiring diagram showing the im provement constituting the present invention.

The type of rail fissure detector car herein shown is the same as that in my Patent No. 1,912,569 granted June 6th, 1933. Thus in Fig. 1 there is shown a portion of a Sperry rail detector car l0, having a generator G therein adapted to supply current to the rail by means of sets of brushes It and I2 adapted to lead current into and out of the rail. Said sets of brushes are supported on a current brush carriage I5 adapted to be supported on the rail R by means such as flanged wheels IS. The current brush carriage may be lowered into engagement with the rail R by means such as pistons ll connected to the carriage and operating within piston cylinders IE to which a source of fluid under pressure is adapted to be supplied when the carriage is to be lowered. When the carriage is to be raised to inoperative position, the fluid supply is cut off and the carriage is raised by means of cables l9 and springs (not shown). Mounted upon the current brush carriage, by means such as limited universal connections 2| comprising loose fitting bolts 26 and springs 21, is a detector carriage 22 adapted to be supported on the rail by means such as rollers 23 and supporting the flaw responsive means which in this case is shown as a pair of detector coils 25 mounted within a holder or sled 28 supported on the detector carriage 22.

From the above description the ordinary operation of the Sperry detector car is apparent, that is to say, as the car runs along the rails with the current brush carriage in lowered position, current is supplied to the sets of brushes l I and [2 to establish an electromagnetic field surrounding the rail which field is uniform except in the region of flaw. Until a region of flaw is encountered, the coils 25, cut the same number of lines of force and nothing happens. If the current supply changes, the lines of force surrounding the rail changes and would ordinarily induce an E. M. F. in each coil but, since the coils are connected oppositely and are of equal inductive capacity, such variations in current supply have no effect upon the coils. On entering a region of flaw, however, one coil will cut a different number of lines of force than the other coil and a differential E. M. F. will be induced which, after being suitably amplified by amplifier A, may be caused to operate a suitable indicator such as pens operating on a moving chart.

One arrangement whereby the output of the amplifier is caused to operate indicating pens on a moving chart is disclosed in my said Patent 1,912,569 and comprises a plurality of relays of different capacities so that a weak output from the amplifier will actuate only one relay while a strong output will actuate two relays, and if each relay is caused to control a pen, then a one-pen indication will indicate a weak region of flaw whereas a two-pen indication will indicate a region of large flaw. Referring to Fig. 2, I have shown the output from the amplifier A as controlling two relays 30 and 3|, said relays co-acting with armatures 30, 3! and controlling the circuits through pen relays 32 and 33 respectively. Said relays co-act with pen armatures 32233 to actuate the pens P and P. The pens P and P normally trace a straight line along the moving chart but when the relays 32, 33 are actuated, due to encountering a region of flaw by the detector coils 25, said pens are caused to make a jog in the straight line to indicate a region of flaw.

It will be understood that every time the car passes over a rail joint there is a very serious distortion of the electromagnetic field due to the construction of the joint which comprises angle bars, bolts, etc. Every joint, therefore, would ordinarily give an indication as of a serious flaw, that is to say, pen relays 32 and 33 would be operated at each rail joint to give a series of indications until the joint was passed over. In order to obviate actuating the pens P and P when a joint is encountered, I provide joint cutout mechanisms which may take the form of fingers 40, 4|, designed to slide along the side of the rail head so that when the angle bar is encountered ata joint said fingers will engage said angle bar and will be tilted about pivots 42, 43 to close sets of contacts and 44' which are connected in parallel so that closing of either one will energize relays 45 and 46. The latter relay 46 attracts its armature 41 to open contacts 48 which are in the circuit of the pen relays 32 and 33. Thus as long as either joint cut-out finger 40 or 4| is on the angle bar, relay 46 is energized and the circuit through relays 32 and 33 is opened to render the pens P and P' ineifective. 'Ihefingers 46 and 4| are so arranged that the rear finger will engage the angle bar before the forward finger has left it. At the same time that relay 46 is energized, relay 45 attracts its armature 49 to close contacts 56 and energize the relay 5| to actuate a joint pen P". The pen P" normally traces a straight line on the moving chart until relay 5| is energized whereupon pen P" is moved out of its normal path and held there until the second joint cut-out finger 4| has left the angle bar whereupon pen P" is returned by suitable spring means to its original position.

Means are provided so that whenever pens P, P are actuated by their relays 32, 33, a paint gun 60 is energized to squirt paint upon the spot where the fiaws are located. The paint gun 60 may be controlled by means of an electrically operated valve 6| which is operated by a relay 62 energized from a suitable source of power, the circuit through relay 62 being controlled by a set of contacts 63. Said contacts 63 are normally open but are energized when an armature 65 is attracted by a coil 66 to close a set of contacts 61, and said coil 66 is adapted to be energized, by reason of the wiring connections shown, whenever either relay 32 or 33 is energized to actuate pens P or P, i. e. whenever relays 30 and 3| are actuated to close contacts 16, 11. It will thus be seen that whenever a flaw pen is actuated the paint gun will be operated.

It was found that sometimes the region of flaw was so small and the speed of the car so relatively great that the time of energization of coil 66, while long enough to attract armature 65, was not suificient to energize relay 64 and hence relay 62 to actuate the paint gun 66. For this reason, I provide in my said Patent 1,912,569 an arrangement for insuring operation of the paint gun once coil 66 attracts this armature 65. For this purpose I provide another coil 63, said coils 66 and 68 being in the form of section of a split coil relay, both together cooperating with armature 65. Coil 66 will be energized first and will attract the armature 65 and as soon as said armature closes contacts 61 there is established a circuit through coil 68 which is independent of the circuit through the pen relays 32 and 33. This circuit extends from the plus side or" the line through coil 68, through a set of contacts 69, through the closed contacts 61, back to the negative side of the line. It will thus be seen that as soon as coil 66 has succeeded in closing the contacts 6! an independent circuit is established through coil 68 that does not depend upon the energization of coils 32 and 33 and will remain energized to keep armature 65 in position to maintain contact 61 closed until the said independent circuit is opened. Such opening cannot take place until the paint gun 69 has been operated by reason of the following construction: When the contacts 61 are closed there is closed also the circuit through paint gun relay 64 and said circuit remains closed until the paint gun relay 64 has attracted its armature -'|0 and drawn said armature completely down until the armature 10 engages spring contact H to open contacts 69 and thus break the circuit through coil 68. Armature 10 does not engage spring contact 1| until contacts 63 have been closed to energize relay 62 and operate the paint gun.

In the construction heretofore employed only the coil 66 was energized when the pen relays 32 and 33 were energized. If coil 66 was energized sufllciently long to close contacts 61, then coil 63 was energized and thereafter, because of the establishment of the independent circuit, coil 68 maintained contacts 61 closed to insure actuation of the paint gun. It sometimes happened, however, because of the fact that 66, 68 were sections of a split coil of a relay, that a short actuation of coil 66, that is to say, of onehalf of the split coil relay, was not suflicient to attract armature 65 and close contact 61. To remedy this condition and prevent possible missing of a region of small fissure, I provide for one additional relay 29 actuated from the output of the amplifier, said relay 29 being responsive to currents of lesser strength than either of the other two relays 30 and 3| so that relay 23 will always be actuated whenever relays 30 and 3| are actuated. Said relay 23 is caused to attract armature 29 to close the circuit through coil 63 whenever a flaw is encountered. We now see that whenever a flaw is encountered both coils 66 and 68 of the split coil relay will be energized and this will be sufficient to attract armature 65 in every case regardless of how short the duration of energization. The circuit from armature 26' leads through contacts 15 and lead 16 to the coil 68. This circuit is in parallel with the independent circuit, described above, which is established through coil 66 once contacts 61 are closed, so that opening of contacts '15 will not interfere with the operation of the paint gun circuit. gized until armature 10 opens contact 69.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

In a flaw detector mechanism for electrical conductors having means responsive to flaw,

said responsive means being adapted to generate an electric impulse in the region of flaw, marking means for placing a mark on the conductor when said responsive means detects a flaw, means including an electric circuit whereby said responsive means actuates said marking means, means including a split coil relay for controlling said circuit, means responsive to said impulses in excess of a predetermined magnitude and adapted to energize one coil of said relay, means responsive to said impulses of lesser magnitude than said preceding means and adapted to energize the other coil of said relay, said second coil, when energized, being insufllcient to close said circuit but suflicient to act as a holding coil, and means for establishing an independent circuit through said second coil when said first circuit is closed.

HARCOURT C. DRAKE.

Said last-named circuit remains ener- 

